Git pager set to diff-highlight does not work in Windows 10

Question

I have set Git's pager option to this

[pager]
    log = diff-highlight 

I downloaded the diff-highlight script from Git's repository 3dbfe2b8 and placed it in my ~/bin folder.

$ where git
C:\Program Files\Git\cmd\git.exe
$ where diff-highlight
C:\Users\andy\bin\diff-highlight

Running git log results in the following error:

$ git log
Can't open diff-highlight: No such file or directory at C:\Users\andy\bin\diff-highlight line 36.
Segmentation fault

On the other hand, the following command runs just fine,

$ git log -p --color | diff-highlight | less -FRSX

This means diff-highlight is available from $PATH , but Git's config cannot find it.

My Git version is 2.12.0.windows.1 .

Answer 1

Recent guidance suggests putting the whole diff-highlight | less -FRSX diff-highlight | less -FRSX string into the pager.XXX config.

This works just fine for me with a Make d version of the current diff-highlight script, although I only use it for pager.diff and interactive.diffFilter .

Answer 2

The Segmentation fault part should, at least, disappear: When a non-existent program is given as the pager, we tried to reuse an uninitialized child_process structure and crashed, which has been fixed with Git 2.35 (Q1 2022).

See commit f917f57 (24 Nov 2021) by Enzo Matsumiya ( ematsumiya ) .
^{(Merged by Junio C Hamano -- gitster -- in commit bb47eee , 10 Dec 2021)}

pager : fix crash when pager program doesn't exist

^{Signed-off-by: Enzo Matsumiya}

When prepare_cmd() fails for, eg, pager process setup, child_process_clear() frees the memory in pager_process .args, but .argv was pointed to pager_process .args.v earlier in start_command() , so it's now a dangling pointer.

setup_pager() is then called a second time, from cmd_log_init_finish() in this case, and any further operations using its .argv, eg strvec_*, will use the dangling pointer and eventually crash.
According to trivial tests, setup_pager() is not called twice if the first call is successful.

This patch makes sure that pager_process is properly initialized on setup_pager() .
Drop CHILD_PROCESS_INIT from its declaration since it's no longer really necessary.

Add a test to catch possible regressions.

Reproducer:

 $ git config pager.show INVALID_PAGER $ git show $VALID_COMMIT error: cannot run INVALID_PAGER: No such file or directory [1] 3619 segmentation fault (core dumped) git show $VALID_COMMIT